#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/sem.h>
#include<sys/ipc.h>

#define _PATH_ "."
#define _PROJ_ID 0x6666
 struct sembuf;

int creat_sem(int nsems);
int get_sem();
int init_sem(int semid,int whitch);
int p_sem_op(int semid,int which);
int v_sem_op(int semid,int which);
int destroy_sem(int sem_id);
